swap out extend for underscore
use _.defaults throughout
Make frame event type an option
clearer text around options, port selectability
tidy up docs
Merge branch 'master' into nicer_events

Conflicts:
	leap.js
	leap.min.js
accumulate gestures across mutliple frames
grab gestures first
re-build
Merge pull request #48 from leapmotion/nicer_events

Nicer events